Incidence, outcome and dynamics of out-of-hospital cardiac arrest in the city of Vienna between 2019 and 2023

BACKGROUND: Regional data and trends in survival from out-of-hospital cardiac arrest (OHCA) are vital to improve favourable outcomes. Since the last cardiopulmonary resuscitation (CPR) guideline update, comprehensive OHCA data of the metropolitan area of Vienna, Austria, have been scarce.

METHODS: This retrospective study analysed adult non-traumatic OHCA cases in Vienna between January 2019 and December 2023. It assessed emergency medical service records and clinical patient data and reported incidences, return of spontaneous circulation (ROSC) rates, survival to hospital discharge and neurological outcome. Logistic regression assessed associations between outcomes and predictors, while Poisson regression examined incidence changes before, during and after COVID-19 lockdowns.

RESULTS: During the observation period, the Emergency Medical Service Vienna started CPR in a total of 7433 patients (77.1/100 000 population per year). Sustained ROSC was observed in 24.8%, survival to hospital discharge in 9.3% and a Cerebral Performance Category (CPC) Score of 1 or 2 in 6.8%, similar to prior data. However, patients with witnessed cardiac arrest of suspected cardiac aetiology and an initial shockable rhythm had a substantially higher rate of survival to hospital discharge (39%), and CPC of 1 or 2 (29.6%). Similarly, patients with CPC 1 or 2 before CPR had better outcomes than the overall cohort. During COVID-19, there was a decline in all outcome parameters.

CONCLUSIONS: Survival after OHCA in Vienna seems stable, but significant improvements in outcome parameters are seen in a 'high outcome potential cohort' over the last 15 years. This reaffirms the need to continue focusing on rapid initiation of bystander CPR and early defibrillation.